1 /*
2 * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
26 #include "gc/shenandoah/shenandoahForwarding.hpp"
27 #include "gc/shenandoah/shenandoahHeap.hpp"
28 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
29 #include "gc/shenandoah/shenandoahHeuristics.hpp"
30 #include "gc/shenandoah/shenandoahRuntime.hpp"
31 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/interp_masm.hpp"
34 #include "runtime/sharedRuntime.hpp"
35 #include "runtime/thread.hpp"
36 #ifdef COMPILER1
37 #include "c1/c1_LIRAssembler.hpp"
38 #include "c1/c1_MacroAssembler.hpp"
39 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
40 #endif
41
42 #define __ masm->
43
44 address ShenandoahBarrierSetAssembler::_shenandoah_lrb = NULL;
45
46 void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
47 Register src, Register dst, Register count, RegSet saved_regs) {
48 if (is_oop) {
49 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
50 if ((ShenandoahSATBBarrier && !dest_uninitialized) || ShenandoahLoadRefBarrier) {
51
52 Label done;
53
54 // Avoid calling runtime if count == 0
55 __ cbz(count, done);
56
57 // Is marking active?
58 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
59 __ ldrb(rscratch1, gc_state);
60 if (dest_uninitialized) {
61 __ tbz(rscratch1, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
62 } else {
63 __ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING);
64 __ tst(rscratch1, rscratch2);
65 __ br(Assembler::EQ, done);
66 }
67
68 __ push(saved_regs, sp);
69 if (UseCompressedOops) {
70 if (dest_uninitialized) {
71 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_duinit_narrow_oop_entry), src, dst, count);
72 } else {
73 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_narrow_oop_entry), src, dst, count);
74 }
75 } else {
76 if (dest_uninitialized) {
77 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_duinit_oop_entry), src, dst, count);
78 } else {
79 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_oop_entry), src, dst, count);
80 }
81 }
82 __ pop(saved_regs, sp);
83 __ bind(done);
84 }
85 }
86 }
87
88 void ShenandoahBarrierSetAssembler::shenandoah_write_barrier_pre(MacroAssembler* masm,
89 Register obj,
90 Register pre_val,
91 Register thread,
92 Register tmp,
93 bool tosca_live,
94 bool expand_call) {
95 if (ShenandoahSATBBarrier) {
96 satb_write_barrier_pre(masm, obj, pre_val, thread, tmp, tosca_live, expand_call);
97 }
98 }
99
100 void ShenandoahBarrierSetAssembler::satb_write_barrier_pre(MacroAssembler* masm,
101 Register obj,
102 Register pre_val,
103 Register thread,
104 Register tmp,
105 bool tosca_live,
106 bool expand_call) {
107 // If expand_call is true then we expand the call_VM_leaf macro
108 // directly to skip generating the check by
109 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
110
111 assert(thread == rthread, "must be");
112
113 Label done;
114 Label runtime;
115
116 assert_different_registers(obj, pre_val, tmp, rscratch1);
117 assert(pre_val != noreg && tmp != noreg, "expecting a register");
118
119 Address in_progress(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset()));
120 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
121 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
122
123 // Is marking active?
124 if (in_bytes(ShenandoahSATBMarkQueue::byte_width_of_active()) == 4) {
125 __ ldrw(tmp, in_progress);
126 } else {
127 assert(in_bytes(ShenandoahSATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
128 __ ldrb(tmp, in_progress);
129 }
130 __ cbzw(tmp, done);
131
132 // Do we need to load the previous value?
133 if (obj != noreg) {
134 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
135 }
136
137 // Is the previous value null?
138 __ cbz(pre_val, done);
139
140 // Can we store original value in the thread's buffer?
141 // Is index == 0?
142 // (The index field is typed as size_t.)
143
144 __ ldr(tmp, index); // tmp := *index_adr
145 __ cbz(tmp, runtime); // tmp == 0?
146 // If yes, goto runtime
147
148 __ sub(tmp, tmp, wordSize); // tmp := tmp - wordSize
149 __ str(tmp, index); // *index_adr := tmp
150 __ ldr(rscratch1, buffer);
151 __ add(tmp, tmp, rscratch1); // tmp := tmp + *buffer_adr
152
153 // Record the previous value
154 __ str(pre_val, Address(tmp, 0));
155 __ b(done);
156
157 __ bind(runtime);
158 // save the live input values
159 RegSet saved = RegSet::of(pre_val);
160 if (tosca_live) saved += RegSet::of(r0);
161 if (obj != noreg) saved += RegSet::of(obj);
162
163 __ push(saved, sp);
164
165 // Calling the runtime using the regular call_VM_leaf mechanism generates
166 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
167 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == NULL.
168 //
169 // If we care generating the pre-barrier without a frame (e.g. in the
170 // intrinsified Reference.get() routine) then ebp might be pointing to
171 // the caller frame and so this check will most likely fail at runtime.
172 //
173 // Expanding the call directly bypasses the generation of the check.
174 // So when we do not have have a full interpreter frame on the stack
175 // expand_call should be passed true.
176
177 if (expand_call) {
178 assert(pre_val != c_rarg1, "smashed arg");
179 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
180 } else {
181 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
182 }
183
184 __ pop(saved, sp);
185
186 __ bind(done);
187 }
188
189 void ShenandoahBarrierSetAssembler::resolve_forward_pointer(MacroAssembler* masm, Register dst, Register tmp) {
190 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
191 Label is_null;
192 __ cbz(dst, is_null);
193 resolve_forward_pointer_not_null(masm, dst, tmp);
194 __ bind(is_null);
195 }
196
197 // IMPORTANT: This must preserve all registers, even rscratch1 and rscratch2, except those explicitely
198 // passed in.
199 void ShenandoahBarrierSetAssembler::resolve_forward_pointer_not_null(MacroAssembler* masm, Register dst, Register tmp) {
200 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
201 // The below loads the mark word, checks if the lowest two bits are
202 // set, and if so, clear the lowest two bits and copy the result
203 // to dst. Otherwise it leaves dst alone.
204 // Implementing this is surprisingly awkward. I do it here by:
205 // - Inverting the mark word
206 // - Test lowest two bits == 0
207 // - If so, set the lowest two bits
208 // - Invert the result back, and copy to dst
209
210 bool borrow_reg = (tmp == noreg);
211 if (borrow_reg) {
212 // No free registers available. Make one useful.
213 tmp = rscratch1;
214 if (tmp == dst) {
215 tmp = rscratch2;
216 }
217 __ push(RegSet::of(tmp), sp);
218 }
219
220 assert_different_registers(tmp, dst);
221
222 Label done;
223 __ ldr(tmp, Address(dst, oopDesc::mark_offset_in_bytes()));
224 __ eon(tmp, tmp, zr);
225 __ ands(zr, tmp, markOopDesc::lock_mask_in_place);
226 __ br(Assembler::NE, done);
227 __ orr(tmp, tmp, markOopDesc::marked_value);
228 __ eon(dst, tmp, zr);
229 __ bind(done);
230
231 if (borrow_reg) {
232 __ pop(RegSet::of(tmp), sp);
233 }
234 }
235
236 void ShenandoahBarrierSetAssembler::load_reference_barrier_not_null(MacroAssembler* masm, Register dst, Address load_addr) {
237 assert(ShenandoahLoadRefBarrier, "Should be enabled");
238 assert(dst != rscratch2, "need rscratch2");
239 assert_different_registers(load_addr.base(), load_addr.index(), rscratch1, rscratch2);
240
241 Label done;
242 __ enter();
243 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
244 __ ldrb(rscratch2, gc_state);
245
246 // Check for heap stability
247 __ tbz(rscratch2, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
248
249 // use r1 for load address
250 Register result_dst = dst;
251 if (dst == r1) {
252 __ mov(rscratch1, dst);
253 dst = rscratch1;
254 }
255
256 // Save r0 and r1, unless it is an output register
257 RegSet to_save = RegSet::of(r0, r1) - result_dst;
258 __ push(to_save, sp);
259 __ lea(r1, load_addr);
260 __ mov(r0, dst);
261
262 __ far_call(RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahBarrierSetAssembler::shenandoah_lrb())));
263
264 __ mov(result_dst, r0);
265 __ pop(to_save, sp);
266
267 __ bind(done);
268 __ leave();
269 }
270
271 void ShenandoahBarrierSetAssembler::storeval_barrier(MacroAssembler* masm, Register dst, Register tmp) {
272 if (ShenandoahStoreValEnqueueBarrier) {
273 // Save possibly live regs.
274 RegSet live_regs = RegSet::range(r0, r4) - dst;
275 __ push(live_regs, sp);
276 __ strd(v0, __ pre(sp, 2 * -wordSize));
277
278 satb_write_barrier_pre(masm, noreg, dst, rthread, tmp, true, false);
279
280 // Restore possibly live regs.
281 __ ldrd(v0, __ post(sp, 2 * wordSize));
282 __ pop(live_regs, sp);
283 }
284 }
285
286 void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm, Register dst, Address load_addr) {
287 if (ShenandoahLoadRefBarrier) {
288 Label is_null;
289 __ cbz(dst, is_null);
290 load_reference_barrier_not_null(masm, dst, load_addr);
291 __ bind(is_null);
292 }
293 }
294
295 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
296 Register dst, Address src, Register tmp1, Register tmp_thread) {
297 // 1: non-reference load, no additional barrier is needed
298 if (!is_reference_type(type)) {
299 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
300 return;
301 }
302
303 // 2: load a reference from src location and apply LRB if needed
304 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
305 Register result_dst = dst;
306
307 // Preserve src location for LRB
308 if (dst == src.base() || dst == src.index()) {
309 dst = rscratch1;
310 }
311 assert_different_registers(dst, src.base(), src.index());
312
313 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
314
315 load_reference_barrier(masm, dst, src);
316
317 if (dst != result_dst) {
318 __ mov(result_dst, dst);
319 dst = result_dst;
320 }
321 } else {
322 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
323 }
324
325 // 3: apply keep-alive barrier if needed
326 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
327 __ enter();
328 satb_write_barrier_pre(masm /* masm */,
329 noreg /* obj */,
330 dst /* pre_val */,
331 rthread /* thread */,
332 tmp1 /* tmp */,
333 true /* tosca_live */,
334 true /* expand_call */);
335 __ leave();
336 }
337 }
338
339 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
340 Address dst, Register val, Register tmp1, Register tmp2) {
341 bool on_oop = type == T_OBJECT || type == T_ARRAY;
342 if (!on_oop) {
343 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2);
344 return;
345 }
346
347 // flatten object address if needed
348 if (dst.index() == noreg && dst.offset() == 0) {
349 if (dst.base() != r3) {
350 __ mov(r3, dst.base());
351 }
352 } else {
353 __ lea(r3, dst);
354 }
355
356 shenandoah_write_barrier_pre(masm,
357 r3 /* obj */,
358 tmp2 /* pre_val */,
359 rthread /* thread */,
360 tmp1 /* tmp */,
361 val != noreg /* tosca_live */,
362 false /* expand_call */);
363
364 if (val == noreg) {
365 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), noreg, noreg, noreg);
366 } else {
367 storeval_barrier(masm, val, tmp1);
368 // G1 barrier needs uncompressed oop for region cross check.
369 Register new_val = val;
370 if (UseCompressedOops) {
371 new_val = rscratch2;
372 __ mov(new_val, val);
373 }
374 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), val, noreg, noreg);
375 }
376
377 }
378
379 void ShenandoahBarrierSetAssembler::try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env,
380 Register obj, Register tmp, Label& slowpath) {
381 Label done;
382 // Resolve jobject
383 BarrierSetAssembler::try_resolve_jobject_in_native(masm, jni_env, obj, tmp, slowpath);
384
385 // Check for null.
386 __ cbz(obj, done);
387
388 assert(obj != rscratch2, "need rscratch2");
389 Address gc_state(jni_env, ShenandoahThreadLocalData::gc_state_offset() - JavaThread::jni_environment_offset());
390 __ lea(rscratch2, gc_state);
391 __ ldrb(rscratch2, Address(rscratch2));
392
393 // Check for heap in evacuation phase
394 __ tbnz(rscratch2, ShenandoahHeap::EVACUATION_BITPOS, slowpath);
395
396 __ bind(done);
397 }
398
399
400 void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, Register addr, Register expected, Register new_val,
401 bool acquire, bool release, bool weak, bool is_cae,
402 Register result) {
403 Register tmp1 = rscratch1;
404 Register tmp2 = rscratch2;
405 bool is_narrow = UseCompressedOops;
406 Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword;
407
408 assert_different_registers(addr, expected, new_val, tmp1, tmp2);
409
410 Label retry, done, fail;
411
412 // CAS, using LL/SC pair.
413 __ bind(retry);
414 __ load_exclusive(tmp1, addr, size, acquire);
415 if (is_narrow) {
416 __ cmpw(tmp1, expected);
417 } else {
418 __ cmp(tmp1, expected);
419 }
420 __ br(Assembler::NE, fail);
421 __ store_exclusive(tmp2, new_val, addr, size, release);
422 if (weak) {
423 __ cmpw(tmp2, 0u); // If the store fails, return NE to our caller
424 } else {
425 __ cbnzw(tmp2, retry);
426 }
427 __ b(done);
428
429 __ bind(fail);
430 // Check if rb(expected)==rb(tmp1)
431 // Shuffle registers so that we have memory value ready for next expected.
432 __ mov(tmp2, expected);
433 __ mov(expected, tmp1);
434 if (is_narrow) {
435 __ decode_heap_oop(tmp1, tmp1);
436 __ decode_heap_oop(tmp2, tmp2);
437 }
438 resolve_forward_pointer(masm, tmp1);
439 resolve_forward_pointer(masm, tmp2);
440 __ cmp(tmp1, tmp2);
441 // Retry with expected now being the value we just loaded from addr.
442 __ br(Assembler::EQ, retry);
443 if (is_cae && is_narrow) {
444 // For cmp-and-exchange and narrow oops, we need to restore
445 // the compressed old-value. We moved it to 'expected' a few lines up.
446 __ mov(tmp1, expected);
447 }
448 __ bind(done);
449
450 if (is_cae) {
451 __ mov(result, tmp1);
452 } else {
453 __ cset(result, Assembler::EQ);
454 }
455 }
456
457 #undef __
458
459 #ifdef COMPILER1
460
461 #define __ ce->masm()->
462
463 void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) {
464 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
465 // At this point we know that marking is in progress.
466 // If do_load() is true then we have to emit the
467 // load of the previous value; otherwise it has already
468 // been loaded into _pre_val.
469
470 __ bind(*stub->entry());
471
472 assert(stub->pre_val()->is_register(), "Precondition.");
473
474 Register pre_val_reg = stub->pre_val()->as_register();
475
476 if (stub->do_load()) {
477 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/, false /*unaligned*/);
478 }
479 __ cbz(pre_val_reg, *stub->continuation());
480 ce->store_parameter(stub->pre_val()->as_register(), 0);
481 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
482 __ b(*stub->continuation());
483 }
484
485 void ShenandoahBarrierSetAssembler::gen_load_reference_barrier_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) {
486 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
487 __ bind(*stub->entry());
488
489 Register obj = stub->obj()->as_register();
490 Register res = stub->result()->as_register();
491 Register addr = stub->addr()->as_pointer_register();
492 Register tmp1 = stub->tmp1()->as_register();
493 Register tmp2 = stub->tmp2()->as_register();
494
495 assert(res == r0, "result must arrive in r0");
496
497 if (res != obj) {
498 __ mov(res, obj);
499 }
500
501 // Check for null.
502 __ cbz(res, *stub->continuation());
503
504 // Check for object in cset.
505 __ mov(tmp2, ShenandoahHeap::in_cset_fast_test_addr());
506 __ lsr(tmp1, res, ShenandoahHeapRegion::region_size_bytes_shift_jint());
507 __ ldrb(tmp2, Address(tmp2, tmp1));
508 __ cbz(tmp2, *stub->continuation());
509
510 // Check if object is already forwarded.
511 Label slow_path;
512 __ ldr(tmp1, Address(res, oopDesc::mark_offset_in_bytes()));
513 __ eon(tmp1, tmp1, zr);
514 __ ands(zr, tmp1, markOopDesc::lock_mask_in_place);
515 __ br(Assembler::NE, slow_path);
516
517 // Decode forwarded object.
518 __ orr(tmp1, tmp1, markOopDesc::marked_value);
519 __ eon(res, tmp1, zr);
520 __ b(*stub->continuation());
521
522 __ bind(slow_path);
523 ce->store_parameter(res, 0);
524 ce->store_parameter(addr, 1);
525 __ far_call(RuntimeAddress(bs->load_reference_barrier_rt_code_blob()->code_begin()));
526
527 __ b(*stub->continuation());
528 }
529
530 #undef __
531
532 #define __ sasm->
533
534 void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
535 __ prologue("shenandoah_pre_barrier", false);
536
537 // arg0 : previous value of memory
538
539 BarrierSet* bs = BarrierSet::barrier_set();
540
541 const Register pre_val = r0;
542 const Register thread = rthread;
543 const Register tmp = rscratch1;
544
545 Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
546 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
547
548 Label done;
549 Label runtime;
550
551 // Is marking still active?
552 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
553 __ ldrb(tmp, gc_state);
554 __ mov(rscratch2, ShenandoahHeap::MARKING | ShenandoahHeap::TRAVERSAL);
555 __ tst(tmp, rscratch2);
556 __ br(Assembler::EQ, done);
557
558 // Can we store original value in the thread's buffer?
559 __ ldr(tmp, queue_index);
560 __ cbz(tmp, runtime);
561
562 __ sub(tmp, tmp, wordSize);
563 __ str(tmp, queue_index);
564 __ ldr(rscratch2, buffer);
565 __ add(tmp, tmp, rscratch2);
566 __ load_parameter(0, rscratch2);
567 __ str(rscratch2, Address(tmp, 0));
568 __ b(done);
569
570 __ bind(runtime);
571 __ push_call_clobbered_registers();
572 __ load_parameter(0, pre_val);
573 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
574 __ pop_call_clobbered_registers();
575 __ bind(done);
576
577 __ epilogue();
578 }
579
580 void ShenandoahBarrierSetAssembler::generate_c1_load_reference_barrier_runtime_stub(StubAssembler* sasm) {
581 __ prologue("shenandoah_load_reference_barrier", false);
582 // arg0 : object to be resolved
583
584 __ push_call_clobbered_registers();
585 __ load_parameter(0, r0);
586 __ load_parameter(1, r1);
587 if (UseCompressedOops) {
588 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow));
589 } else {
590 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier));
591 }
592 __ blr(lr);
593 __ mov(rscratch1, r0);
594 __ pop_call_clobbered_registers();
595 __ mov(r0, rscratch1);
596
597 __ epilogue();
598 }
599
600 #undef __
601
602 #endif // COMPILER1
603
604 address ShenandoahBarrierSetAssembler::shenandoah_lrb() {
605 assert(_shenandoah_lrb != NULL, "need load reference barrier stub");
606 return _shenandoah_lrb;
607 }
608
609 #define __ cgen->assembler()->
610
611 // Shenandoah load reference barrier.
612 //
613 // Input:
614 // r0: OOP to evacuate. Not null.
615 // r1: load address
616 //
617 // Output:
618 // r0: Pointer to evacuated OOP.
619 //
620 // Trash rscratch1, rscratch2. Preserve everything else.
621 address ShenandoahBarrierSetAssembler::generate_shenandoah_lrb(StubCodeGenerator* cgen) {
622
623 __ align(6);
624 StubCodeMark mark(cgen, "StubRoutines", "shenandoah_lrb");
625 address start = __ pc();
626
627 Label work, done;
628 __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr());
629 __ lsr(rscratch1, r0, ShenandoahHeapRegion::region_size_bytes_shift_jint());
630 __ ldrb(rscratch2, Address(rscratch2, rscratch1));
631 __ tbnz(rscratch2, 0, work);
632 __ ret(lr);
633 __ bind(work);
634
635 Label slow_path;
636 __ ldr(rscratch1, Address(r0, oopDesc::mark_offset_in_bytes()));
637 __ eon(rscratch1, rscratch1, zr);
638 __ ands(zr, rscratch1, markOopDesc::lock_mask_in_place);
639 __ br(Assembler::NE, slow_path);
640
641 // Decode forwarded object.
642 __ orr(rscratch1, rscratch1, markOopDesc::marked_value);
643 __ eon(r0, rscratch1, zr);
644 __ ret(lr);
645
646 __ bind(slow_path);
647 __ enter(); // required for proper stackwalking of RuntimeStub frame
648
649 __ push_call_clobbered_registers();
650
651 if (UseCompressedOops) {
652 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow));
653 } else {
654 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier));
655 }
656 __ blr(lr);
657 __ mov(rscratch1, r0);
658 __ pop_call_clobbered_registers();
659 __ mov(r0, rscratch1);
660
661 __ leave(); // required for proper stackwalking of RuntimeStub frame
662 __ bind(done);
663 __ ret(lr);
664
665 return start;
666 }
667
668 #undef __
669
670 void ShenandoahBarrierSetAssembler::barrier_stubs_init() {
671 if (ShenandoahLoadRefBarrier) {
672 int stub_code_size = 2048;
673 ResourceMark rm;
674 BufferBlob* bb = BufferBlob::create("shenandoah_barrier_stubs", stub_code_size);
675 CodeBuffer buf(bb);
676 StubCodeGenerator cgen(&buf);
677 _shenandoah_lrb = generate_shenandoah_lrb(&cgen);
678 }
679 }